The sense of taste plays a critical role in governing intake of important nutrients and providing protection from ingestion of harmful substances. When the sense of taste is compromised by therapeutic drugs, radiation therapy or aging, these fundamental roles are jeopardized and the nutritional status of the individual can suffer. Taste dysfunctions are poorly understood in a large part because basic information such as the identity of neurotransmitter(s) is still a mystery. The experiments outlined in this proposal are designed to identify the neurotransmitters at taste bud synapses. Identification of the transmitter(s) involved in taste transduction will help determine which agents affect taste and how taste is affected by aging and disease processes. The research will also answer one of the fundamental questions in the chemical senses. The proposed research will focus on four Specific Aims: 1) To determine whether taste stimulation elicits the release of an aminergic neurotransmitter from taste buds in a Ca2+-dependent manner; 2) To identify which biogenic amines are released when taste cells are stimulated; 3) To test whether the same or different aminergic transmitters are released in response to different taste stimuli; 4) To measure vesicular release of transmitter from isolated individual Necturus taste cells.